BackTools Mod (1.20.1, 1.19.4) - Putting the Tools on your Back - 9Minecraft.Net
Back Tools Mod 1.16.5/1.15.2/1.12.2 for Minecraft
BackSlot - Minecraft Mods - CurseForge
Back Tools - Mod Details | Minecraft Mod Guide - GameWith
i can't find the name of this resource pack/mod where you can put your item like at this picture. it looks like back tools, but it is not actually back tools :